The history of Ancient Rome -- the Rome of the Caesars, the legions, the Appian way and the Colosseum-- begins about 753 B.C. and ends at least 1200 years later. The end came either in 476 A.D. when rule of the Western part of the empire passed officially to barbarians, or in 1453 A.D. when Constantinople, the capitol of Rome in the east fell to the Turkish regime. Sources differ in this regard and it is useful to specify which part of Roman history and which region of Rome to which one refers.
The period 753 B.C. to 509 B.C. can be referred to as the Monarchy period. It encompasses the founding of the city itself and ends with the last year of the rule of Tarquinius Superbus. The period to follow, the Roman Republic, begins in 509 B.C. and ends with the founding of the Empire in 27 B.C. with the ascension of Augustus Caesar to the throne as the first emperor. However this transition was not done in a year but took a few years to accomplish.
The initial period establishing the Roman Empire conceivably took place in the period 31 B.C. to 14 A.D. This period is marked by the triumph of Octavian in 31 B.C. at the end of the civil war for control of the Roman Republic (32-31 B.C.) and the death of Caesar’s last remaining rivals, Mark Antony and Cleopatra in 30 B.C.. Octavian's victory was followed by his ascension to the throne in 27 B.C. when Octavian took the name Augustus Caesar. The period ends with the death of Augustus in 14 A.D. by which time popular elections had all but been abandoned. and the Empire had truly replaced the Republic.
- The Fall of the Roman Republic BBC History 2006-09-11. Author: Mary Beard, professor of Classics at the University of Cambridge.
- Ancient Rome Timeline BBC Ancient History. Author: Dominic Berry, senior lecturer in Classics and Roman history at the University of Leeds.
- The Late Republic, 133-30 B.C. Ancient Rome: From its founding to decline. Author: Gary Edward Forsythe: Assistant Professor of Classical Languages and Literatures, University of Chicago
- Augustus (63 BC - AD 14) BBC History
- Cassius Dio: Roman History Cassius Dio (circa late 2nd to early 3rd century), translated by Earnest Cary (1914 through 1927). Loeb Classical Library, 9 volumes: Harvard University Press
- Augustus Caesar and the Pax Romana Kries, Steven (2007) The History Guide